Rules and Guidelines
Want to participate in the discussions? Please read our Community Rules and Guidelines. Need some help? Visit Support and Answers.

  • State Not Answered
  • Locked Locked
  • Replies 2 replies
  • Subscribers 32 subscribers
  • Views 1892 views
  • Users 0 members are here
Options
You may also be interested in
This discussion has been locked.
You can no longer post new replies to this discussion. If you have a question you can start a new discussion

Derating factors for Cable trays with cover

Former Community Member
Former Community Member
“Ampacity of cables in covered tray" developed by Engmann  concluded that the ampacities of cables in ventilated trays with cover are 70% to 75% of the open-top tray ampacities .

I can't find such derating factors in BS 7671 neither in IEC 60364-5-52. Please clarify.
Parents
  • Former Community Member
    0 Former Community Member
    They aren't published in BS 7671 - and there are a variety of methods of lidding including ventilated and unventilated  - which perhaps explains why


    Whilst ampacity reduction to 75% is fairly normal, when tested, it's often less as the flat steel cover is quite a good radiant emitter


    I don't think you'll find definitive published derating factors, this is very much one for the engineer to make a judgement


    Regards


    OMS
Reply
  • Former Community Member
    0 Former Community Member
    They aren't published in BS 7671 - and there are a variety of methods of lidding including ventilated and unventilated  - which perhaps explains why


    Whilst ampacity reduction to 75% is fairly normal, when tested, it's often less as the flat steel cover is quite a good radiant emitter


    I don't think you'll find definitive published derating factors, this is very much one for the engineer to make a judgement


    Regards


    OMS
Children
No Data

Community Rules & Guidelines